You can always build a computer without WiFI/BT, they are external components.

I was commenting the user case of using the PC you already own via Tailscale.

If you have to think about a new hardware and don't want to be registered as "bitcoin user" a SeedSigner is a really good, if not perfect, choise: off-the-shelf components for less than $50 and open source software:
https://nostr.com/nevent1qqsqqqqqw6nzsdsk0qh3ha7hsvcepx9jaqx7u6t2y0fra936wrffkyszypaaaaa7ytwcuk05vq8qgj498gw0jadfm37j0h6cxw780kmcffvq2e7s7w4